1. Field of the Invention
The present invention relates to a transmission for a vehicle that includes a gear shifting mechanism provided with a plurality of selectively establishable gear trains for speed steps between a speed change input shaft and a speed change output shaft. A clutch is adapted to switch between connection and disconnection of power transmission between a power source output shaft and the speed change input shaft with a shift drum turnably carried by an engine case so as to selectively establish the gear trains in response to a turning position. A shift spindle is turnably attached to the engine case so as to turn in response to shifting operation. A shift position changing drive means is provided having an arm member capable of turning around the axis of the shift spindle and being adapted to drivingly turn the shift drum in response to turning of the shift spindle.
In addition, the present invention relates to a transmission for a vehicle that includes a plurality of gear trains for speed steps accommodated in an engine case so as to enable selective engagement. A shift drum is turnably carried by the engine case so as to selectively establish the gear trains in response to a turning position. Shifting position changing drive means are provided for covering one end of the shift drum so as to drivingly turn the shift drum in response to a shift operation. A shifting position sensor detects which one of the gear trains is established.
2. Description of Background Art
As disclosed in Japanese Patent Laid-open No. Hei 2-212675, a transmission for a motorcycle is known that is devised to drivingly turn a shift drum by turning an arm member secured to a shift spindle by turning of the shift spindle.
The transmission as disclosed in Japanese Patent Laid-open No. Hei 2-212675 requires that when a shifting operation is performed to turn a shift spindle, if it is stopped in the power transmission state of a clutch, it is stopped at the neutral position. In addition, when control is exercised to reduce output torque of an engine during the shifting, if the shifting operation is stopped at the neutral position as described above, the above control is continued as a result of a determination in which the shifting operation is not finished. Further, there is a possibility that a shifting operational load may excessively be applied to component parts such as a shift drum and the like.
A transmission for a motorcycle is disclosed in Japanese Patent Laid-open No. 2002-67741 that is devised to directly detect the turning amount of a shift drum by a shifting position sensor in order to detect a shifting position.
The transmission as disclosed in Japanese Patent Laid-open No. 2002-67741 includes a shifting position sensor often disposed inside an engine case. In such a situation, it is desired to enhance the maintenance performance for the shifting position sensor.